Electrodeposition of zinc coatings from the solutions of zinc oxide in imidazolium chloride/urea mixtures

To solve the inherent disadvantages in conventional processes for electrodeposition of zinc, it’s necessary to develop more high-efficiency and environmentally friendly electrolytes. In this work, it was found that the dissolution of ZnO was remarkably enhanced in some imidazolium chloride by the addition of urea, and the solubility of ZnO in 1:1 [Amim]Cl/urea mixture was as high as 8.35 wt% at 373.2 K. Electrochemical measurements showed that zinc could be readily electrodeposited from the solutions of ZnO. Bright, dense and well adherent zinc coatings with good purity were obtained from 0.6 M solution of ZnO in 1:1 [Amim]Cl/urea at 323.2 343.2 K. It’s expected that the solutions of ZnO in imidazolium chloride/urea mixtures have the potential to replace the traditional electrolytes, especially toxic zinc chloride-based ones for zinc electroplating, as well as preparation of zinc materials.     

A facile and convenient method for synthesis of alkyl thiocyanates under homogeneous phase transfer catalyst conditions

A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide （TBAB） as a phase transfer catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification.     

Conversion of xylose and xylan into furfural in biorenewable choline chloride–oxalic acid deep eutectic solvent with the addition of metal chloride

An environmentally benign processing approach for furfural production from xylose and xylan under very mild conditions(353–373 K) was developed with the addition of metal chlorides in ChCl–oxalic acid(a deep eutectic solvent(DES)) synthesized from cheap and renewable starting materials). ChCl–oxalic acid acted as both a Br?nsted acid catalyst and a reaction medium in this catalytic route. In addition, a biphasic system with methyl isobutyl ketone as an extracting reagent(DES/MIBK) to further increase furfural yield was also proposed. This processing approach for producing furfural eliminated the large energy consumption for high pressure saturated steam and the generation of acidic effluent, which was very difficult to handle. The whole catalytic system was more environmentally friendly compared with the commercial process for furfural production.     

A facile electrochemical method for the synthesis of new sulfonamide derivatives of potential biological significance

The electrochemical synthesis of some new sulfonamide derivatives was carried out via the electrochemical oxidation of 2,3-dihydrophthalazine-l,4-dione （1） in the presence of arylsulfinic acids （2a and 2b） as nucleophiles. The results show that, the electrogenerated phthalazine-l,4-dione （lox） participates in a Michael type addition reaction with 2a or 2b and via an EC mechanism to produce the corresponding sulfonamide derivatives. This method provides a one-pot procedure for the synthesis of new sulfonamide derivatives of potential biological significance in good yields without using toxic reagents at a carbon electrode in an environmentally friendly manner.     

碘甲烷在碳酸二甲酯直接合成中的作用

Dimethyl carbonate (DMC) is an environmentally friendly compound and a substitutive intermediate for highly toxic phosgene or dimethyl sulfate in carbonylation and methylation reactions as well as a promising octane booster. The common methods for its preparation are the oxidative carbonylation of methanol catalyzed by a variety of transition metal ions and the transesterification of ethylene carbonate or propene carbonate with methanol[1]. The direct synthesis of DMC from carbon dioxide and methanol is a challenging route in which the most abundant carbon resources and a main greenhouse gas is used as feedstock. A new method for the direct synthesis of DMC catalyzed by the methoxide of main group metal has attracted more and more attention since it was reported[2～6] . However the lower conversion of the reaction has become the main obstacle for its application. In this letter, an efficient promoter for the direct synthesis of DMC is reported.     

Visible light induced the high-efficiency spirocyclization reaction of propynamide and thiophenols via recyclable catalyst Pd/ZrO2

A new method for the synthesis of 3-thioazaspiro[4,5]trienones was developed using Pd nanoparticle catalysts,which are highly efficient,environmentally friendly and recyclable.Alkynes and thiophene phenols are effectively cyclized by Pd/ZrO2 catalyst under visible light irradiation.The present protocol simply utilizes visible light as the safe and ecofriendly energy source,and the Pd/ZrO2 nanocomposite as photocatalyst provides a simple and practical approach to various 3-thioazaspiro[4,5]trienones in moderate conditions to high yields.     

Some Organic Reactions in Supercritical Carbon Dioxide

Organic reactions in supercritical carbon dioxide (scCO2) have facilitated great progress in recent years . ScCO2, as an environmentally friendly reaction medium, may be a substitute for 1 volatile and toxic organic solvents and show some special advantages. Firstly, CO2 is inexpensive, nonflammable, nontoxic and chemical inert under many conditions. Secondly, scCO2 possesses hybrid properties of both liquid and gas, to the advantage of some reactions involving gaseous reagents. Control o…     

One—Pot Synthese of 3,4—Dihydropyrimidine—2（1H）—thiones Catalyzed by La（OTf）3

A general and practical procedure for the syntheses of 3,4-di-hydropyrimidine-2(1H)-thiones by a one-pot condensation of aldehyde,β-ketoester or β-diketone and thiourea using La(OTf)3 as the catalyst is described.Mild reaction conditions,excellent yields as well as the environmentally friendly character of La(OTf)3 make it an important alternative to the classic acid-catalyzed Biginelli‘s reaction.     

Influence of Geometric Structure of Immobilized Aluminium Chloride Catalyst on Catalytic Property in Isobutene Polymerization

AlCl3 is one of the most important and widely used Friedel-Crafts catalysts. As a catalyst, it has serious drawbacks. Besides being corrosive, it also causes other troubles, such as difficulty to separate from products and production of large amounts of environment-polluting waste, which have increasingly hindered its successful application in chemical and related industries. Scientists have been striving for a long time to change AlCl3 into an environmentally friendly catalyst through immob…     

Poly(4-vinylpyridinium tribromide) as metal-free, green and recoverable oxidizing polymer for the chemoselective oxidation of sulfides into sulfoxides

Poly(4-vinylpyridinium tribromide) was prepared from poly(4-vinylpyridin) and used for the selective oxidation of a variety of sulfides to the corresponding sulfoxides.The oxidation reaction was carried out heterogeneously in acetone/water,as green solvent, at room temperature.     

微波促进环境友好条件下，碳酸二甲酯为甲基化试剂合成二甲基化1,6-二氢嘧啶酮

本文报道以碳酸二甲酯（DMC）为甲基化试剂实现3，4-二氢嘧啶-2-硫酮甲基化反应的有效方法。在微波辐射下，弱碱MgO和四丁基溴化胺的存在下反应即可完成得到目标产物。DMC的使用避免了剧毒烷基化试剂—碘甲烷或硫酸二甲酯的使用，微波技术的使用极大的缩短了反应时间。通过元素分析、¹H NMR,IR 和单晶X射线衍射确证了它们的结构，提出了反应机理。     

Mild and Convenient Synthesis of 1,2‐Dihydroquinolines from Anilines and Acetone Catalyzed by Ytterbium(III) Triflate in Ionic Liquids

A mild, convenient, and efficient process has been developed for the synthesis of 2,2,4‐trimethyl‐1,2‐dihydroquinolines by the reaction of anilines with acetone catalyzed by ytterbium(III) triflate [Yb(OTf)₃] in ionic liquids. The catalyst and ionic liquids can be easily recovered and reused, making this method friendly and environmentally acceptable.     

Novel,environmentally friendly crosslinking system of an epoxy using an amino acid: Tryptophan‐cured diglycidyl ether of bisphenol A epoxy

Tryptophan, an amino acid, has been used as a novel, environmentally friendly curing agent instead of toxic curing agents to crosslink the diglycidyl ether of bisphenol A (DGEBA) epoxy resin. The curing reaction of tryptophan/DGEBA mixtures of different ratios and the effect of the imidazole catalyst on the reaction have been evaluated. The optimum reaction ratio of DGEBA to tryptophan has been determined to be 3:1 with 1 wt % catalyst, and the curing mechanism of the novel reaction system has been studied and elucidated. In situ Fourier transform infrared spectra indicate that with the extraction of a hydrogen from NH₃⁺ in zwitterions from tryptophan, the formed nucleophilic primary amine and carboxylate anions of the tryptophan can readily participate in the ring‐opening reaction with epoxy. The secondary amine, formed from the primary amine, can further participate in the ring‐opening reaction with epoxy and form the crosslinked network. The crosslinked structure exhibits a reasonably high glass‐transition temperature and thermal stability. A catalyst‐initiated chain reaction mechanism is proposed for the curing reaction of the epoxy with zwitterion amino acid hardeners. The replacement of toxic curing agents with this novel, environmentally friendly curing agent is an important step toward a next‐generation green electronics industry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 181–190, 2007     

Dispersive micro‐solid‐phase extraction using carbon‐based adsorbents for the sensitive determination of verapamil in plasma samples coupled with capillary electrophoresis

A dispersive micro‐solid‐phase extraction procedure coupled with capillary electrophoresis ultraviolet detection was developed for determination of verapamil in plasma samples. Graphene oxide/polydopamin was synthesized by a one‐step polymerization method, and graphene oxide/Fe₃O₄ (magnetic graphene oxide) nanocomposite was prepared by coprecipitation method. Moreover, they were fully characterized. The use of hazardous and water‐immiscible solvents was scaled down, and only 500 μL of acetone was required as the desorption solvent. The detector response concentration plots were linear in the range of 5–500 ng/mL, and the proposed method was validated according to guidelines. The precision and accuracy were less than 15%. Dispersive micro‐solid‐phase extraction method provides a rapid, environmentally friendly, and sensitive analysis for the verapamil in patient plasma samples, which is adequate for therapeutic drug monitoring and pharmacokinetic studies.     

The Mn‐zeolite/Graphite Modified Glassy Carbon Electrode: Fabrication,Characterization and Analytical Applications

In this work, low‐cost and environmentally friendly natural zeolite exchanged with Mn²⁺ cations was used for the first time to modify the glassy carbon electrode with the aim to obtain a fast and simple sensor for voltammetric determination of paracetamol (PAR). The Mn‐zeolite/graphite modified glassy carbon electrode (MnZG?GCE) was prepared by evaporation of solvent from dispersion of the zeolite/graphite mixture with the polymer in acetone. The electrochemical characteristics of MnZG?GCE were conducted by electrochemical impedance spectroscopy and cyclic voltammetry. Compared with graphite modified GCE (G?GCE), MnZG?GCE exhibited better electrochemical parameters, which confirms the superiority of applying zeolite in the proposed sensor. The optimization of the pH‐value of supporting electrolyte and instrumental parameters were carried out. The peak current was proportional to the concentration of PAR in a phosphate buffer saline of pH 6.0 in the range from 0.029 to 0.69 mg L^?1 (R=0.9997) with limit of detection of 8.8 μg L^?1. Finally, the proposed electrode was successfully applied to determine the paracetamol in pharmaceutical formulation and certified reference materials. The satisfactory recoveries, which ranged from 89.2 to 102.7 %, were obtained for all studied samples. It confirmed the attractiveness of relatively inexpensive, easy to fabricate and non‐toxic MnZG?GCE in determination of PAR in complicated matrixes.     

A One‐pot,Efficient Synthesis of Polyfunctionalized Pyrido[2,3‐d]pyrimidines and Uncyclized Adducts by Aldehydes, 1,3‐Dicarbonyl Compounds,and 6‐Aminouracils

A one‐pot, efficient protocol for the synthesis of polyfunctionalized pyrido[2,3‐d]pyrimidines and uncyclized adducts by 6‐aminouracils in poly(ethylene glycol) 200/H₂O or AcOH was described. An interesting family of pyrido[2,3‐d]pyrimidines and uncyclized adducts bearing fused pharmacological active units are prepared. The reaction is free of toxic solvents and catalysts, has simple workup procedure, and has high atom economy, making it more environmentally friendly and suitable for large‐scale operations.     

Cyanovinylation of Aldehydes: Organocatalytic Multicomponent Synthesis of Conjugated Cyanomethyl Vinyl Ethers

A novel organocatalytic multicomponent cyanovinylation of aldehydes was designed for the synthesis of conjugated cyanomethyl vinyl ethers. The reaction was implemented for the synthesis of a 3-substituted 3-(cyanomethoxy)acrylates, using aldehydes as substrates, acetone cyanohydrin as the cyanide anion source, and methyl propiolate as the source of the vinyl component. The multicomponent reaction is catalyzed by N-methyl morpholine (2.5 mol%) to deliver the 3-(cyanomethoxy)acrylates in excellent yields and with preponderance of the E-isomer. The multicomponent reaction manifold is highly tolerant to the structure and composition of the aldehyde (aliphatic, aromatic, heteroaromatics), and it is instrumentally simple (one batch, open atmospheres), economic (2.5 mol% catalyst, stoichiometric reagents), environmentally friendly (no toxic waste), and sustainable (easy scalability).     

One‐Pot Three‐Component Synthesis of 2‐Amino Pyrimidines in Aqueous PEG‐400 at Ambient Temperature

Amino pyrimidines have been synthesized by a one‐pot procedure under environmentally friendly reaction conditions at room temperature. The use of aqueous PEG‐400 circumvents the problems associated with the toxic, hazardous organic solvents and oxidizing agents.     

Precipitation of dispersed silver particles using acetone as reducing agent

A novel environmentally friendly solution-based method for preparing dispersed silver particles is described. The simple and convenient approach consists in heating silver oxide particles dispersed in a highly alkaline water/acetone mixture. The data presented clearly show that acetone reduces completely and rapidly Ag(2)O particles to metallic silver at 60°C. A mechanism explaining the provenance of the electrons responsible for the reduction of silver is proposed.     

Comparison of membrane assisted solvent extraction,stir bar sorptive extraction,and solid phase microextraction in analysis of tetramine in food

Three environmentally friendly extraction techniques, membrane assisted solvent extraction (MASE), stir bar sorptive extraction (SBSE), and headspace solid phase microextraction (HS‐SPME), were compared for the direct analysis of the highly toxic rodenticide tetramine in food. The optimized MASE method was applied to seven foods fortified with tetramine and compared to previously reported SBSE and HS‐SPME results. Parameters such as the standard addition linearity (MASE (0.964–0.999), SBSE (0.966–0.999), HS‐SPME (0.955–0.999)), recovery (MASE (12–86%), SBSE (36–130%), HS‐SPME (50–200%)), reproducibility (MASE (3.0–30%), SBSE (4.4–9.6%), HS‐SPME (1–12%)), and LOD (MASE (1.6–6.4 ng/g), SBSE (0.2–2.1 ng/g), HS‐SPME (0.9–4.3 ng/g)) were compared.